<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        div{
            position: absolute;
            left: 0;
            width: 100px;
            height: 100px;
            background-color: pink;
        }
    </style>
</head>
<body>
    <div></div>
    <script>
        var div=document.querySelector('div');
        var startX=0;
        var startY=0;
        var x=0;//获得盒子原来的位置
        var y=0;
        div.addEventListener('touchstart',function(e){
            //获得手机初始坐标
            startX=e.targetTouches[0].pageX;
            startY=e.targetTouches[0].pageY;
            x=this.offsetLeft;
            y=this.offsetTop;
        });
        div.addEventListener('touchmove',function(e){
            //计算手指移动距离,手指移动之后的坐标减去手指初始的坐标
           var moveX=e.targetTouches[0].pageX-startX;
           var moveY=e.targetTouches[0].pageY-startY;
           //移动盒子 盒子原来的位置+手指移动的距离
           this.style.left=x+moveX+'px';
           this.style.top=y+moveY+'px';
           e.preventDefault();//阻止屏幕滚动的默认行为
        });
    </script>
</body>
</html>